[Non-invasive evaluation of pressure gradients in aortic stenosis using Doppler ultrasound].

In 35 consecutive patients with aortic stenosis, noninvasive assessment of pressure gradients was performed using a continuous wave Doppler ultrasound technique prior to left heart catheterization. Maximum blood flow velocity in the ascending aorta and time from aortic valve opening to peak velocity in relation to left ventricular ejection time (TPV) were measured. Doppler data proved reliable in predicting a pressure gradient above or below 50 mm Hg (sensitivity 89% and specificity 88%). Pressure gradients calculated from the frequency shift of the ultrasound wave correlated well with pressure measurements obtained at cardiac catheterization in 31 patients with adequate Doppler velocity signals (r = 0.85, p less than 0.001). In all 4 patients with inadequate velocity signals a pressure gradient above 50 mm Hg could still be predicted by an abnormally delayed timing of peak velocity in systole (TPV greater than 0.5).